Vapor Chamber Wick Structure for Faster Two-Phase Boiling
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Solution Overview
Problem
Conventional vapor chambers have limited evaporation efficiency due to a small contact area between the working fluid and the chamber, leading to slow heat dissipation in high heat flux applications, such as advanced ICs, as they primarily facilitate simple evaporation and film boiling, which is insufficient for quick heat transfer.
Innovation Solution
The vapor chamber design features a wick structure with projected and recessed sections on the evaporating side, allowing for enhanced two-phase flow boiling by creating spaces for vapor bubbles to escape, enabling pool boiling, film boiling, and flow boiling, thereby increasing latent heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional vapor chamber with a basic wick structure is used, then the structure is simple and easy to manufacture, but the evaporation efficiency is low and heat dissipation is slow
Solution Approach 1:
The wick structure is segmented into multiple functional zones: a first wick structure in the liquid reservoir area for liquid supply, and a second wick structure in the evaporation area for vapor generation. This segmentation allows each zone to perform its specific function optimally, improving overall heat dissipation efficiency while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
Different wick structures are applied to different locations within the vapor chamber. The first wick structure has different material properties or geometric characteristics suited for liquid reservoir functions, while the second wick structure has properties optimized for evaporation. This local differentiation improves heat dissipation performance without requiring complete redesign of the entire structure
2Productivity
If the contact area between working fluid and vapor chamber is small, then the structure is simple, but the evaporation efficiency is low and it takes a long time to vaporize the working fluid
Solution Approach 1:
The wick structures extend vertically into the liquid reservoir, creating three-dimensional contact pathways between the working fluid and the vapor chamber walls. This dimensional extension dramatically increases the effective contact area without expanding the horizontal footprint, enabling faster vaporization rates while maintaining a compact overall structure
3Power
If only evaporation and film boiling occur in the vapor chamber, then the phase transition is simple and the structure is basic, but the latent heat exchange ability is insufficient for high heat flux applications
Solution Approach 1:
The dual wick structure configuration enables the system to transition between different heat transfer regimes (evaporation, film boiling, and pool boiling) by changing the operational parameters such as heat flux density and fluid saturation. This allows the vapor chamber to achieve high latent heat exchange ability comparable to advanced heat pipes without requiring complex multi-phase transition mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances latent heat exchange ability, allowing for faster and more efficient heat dissipation by enabling fiercer phase transitions and simultaneous occurrence of different boiling types, addressing the need for immediate heat transfer in high heat generating chips and dies.
Implementation Method 1
the working fluid in the vapor chamber transfers heat through the mechanism of latent heat of phase transition
Implementation Method 2
the working fluid absorbs the heat transferred from the heat source to the evaporating side and is heated
Implementation Method 3
a vapor/liquid (or boiling/condensing) two-phase heat exchange takes place
Implementation Method 4
the working fluid in the airtight chamber is vaporized or boiled and evaporation occurs on the wall surface
Implementation Method 5
the vapor is then condensed and flows back to the heated area through the wick structure
Implementation Method 6
the capillary wick structure in the vapor chamber enables only simple evaporation or evaporation and film boiling
Data Source
AI summary
A vapor chamber with structure for enhancing two-phase flow boiling includes a main body formed of a first and a second plate member, which are correspondingly closed to each other to define an airtight chamber between them. The airtight chamber has a condensing side and an evaporating side and has a working fluid filled therein. The evaporating side is formed on its surface with a plurality of projected sections and a plurality of recessed sections and has a wick structure provided thereon. The projected sections extend through and project beyond the wick structure, and the recessed sections are located below the wick structure without being filled by the wick structure to thereby form spaces for receiving the working fluid. The provision of the projected and the recessed sections enables the vapor chamber to provide largely enhanced two-phase flow boiling effect in the airtight chamber.